This invention concerns magnetic head sliders (the sliders is not contacting but flying when said sliders drive on magnetic disks in this specification), which reduce head slider flying height (in the following, only flying height) in the high altitudes, when flying height over magnetic disk full face of magnetic head slider in the flatland low altitudes is approximately equalized, and concerns a magnetic disk unit using it.
It is important to narrow flying height defined as a clearance between a magnetic disk which rotates and a magnetic head slider in order to attempt high recording density of the magnetic disk apparatus. It is also desired that flying height is approximately equalized over the magnetic disk full face.
Narrowing of flying height increases the possibility of contacting the magnetic head to the magnetic disk and the magnetic head slider crashes, and there is the danger of destroying record information on the magnetic disk when both contact conditions are very inferior.
Therefore, from the viewpoint of the improvement in the recording density, decreasing flying height of the magnetic head slider is wanted, and the contradictory demand is wanted from the viewpoint of the reliability of the magnetic disk apparatus.
Laid open 6-325530 and laid open 6-333354 are examples of the conventional technology whose flying height is approximately equalized over the magnetic disk full face. In the laid open 6-325530, a positive pressure slider equalizes flying height over a magnetic disk full face approximately by using a shallow step bearing of 0.7 μm or less. Laid open 6-333354 a negative pressure slider equalizes flying height over a magnetic disk full face approximately by using a combination of barreled side rail with the cross rail of magnetic head slider which is postponed in the cross-direction.
(1) Dispersion of flying height by processing dispersion (slight difference between the sliders which made up) of magnetic head slider, (2) lowering of flying height by the seek operation, (3) lowering of flying height by atmospheric pressure lowering in the highland, etc. must be respectively reduced in order to narrow flying height of magnetic head slider, while the reliability of the magnetic disk apparatus is kept.
Especially, flying height lowers by the increase of the aerial mean free path (the length which the air moleculars advance during the collisions between air moleculars) which is working fluid e.g. air of the magnetic head slider, when the magnetic disk apparatus is used in the highland, if it says about (3) in addition. Moreover, the effect on the reliability of the magnetic disk apparatus which is affected by the lowering of flying height caused by the lowering of atmospheric pressure is great, because magnetic head slider will keep be operated at flying height which always lowers.
Then, it is an important problem that the lowering quantity of flying height in the highland is to be reduced as less as possible and the lowering quantity is to be maintained equivalent over magnetic disk full face in the flatland to say noting of equalizing quantity of flying height (the levitation profile) over magnetic disk full face in the flat ground, as the narrowing of flying height promotes.
Laid open 6-325530 showed a positive pressure slider and laid open 6-333354 showed a negative pressure slider, both of them equalizes flying height over the magnetic disk full face in the flatland approximately, and can reduce flying height change by the processing dispersion and seek operation. However analyzed by the present inventors, the improvement on the above points was desired until now, without considering the flying height lowering in the highland at all.